GB2438436A

GB2438436A - Electronic ink panel having three types of electrophoretic particles each responsive to a different voltage level

Info

Publication number: GB2438436A
Application number: GB0624955A
Authority: GB
Inventors: Chang Yeon Kim; Dae Won Kim
Original assignee: LG Philips LCD Co Ltd
Current assignee: LG Display Co Ltd
Priority date: 2006-05-24
Filing date: 2006-12-14
Publication date: 2007-11-28
Anticipated expiration: 2026-12-14
Also published as: JP2007316586A; CN101078849A; GB0624955D0; US7834844B2; KR20070112943A; JP4584239B2; US20070273956A1; GB2438436B; FR2901615A1

Abstract

An electronic ink panel, capable of displaying full colour gradation without a colour filter, comprises: an electronic ink layer (210) comprising first to third particle types (222, 224, 226); a first substrate (202) in which a first electrode (206) facing one surface of the electronic ink layer (210) is formed; and a second substrate (204) facing the first substrate with second electrodes (208) defining pixel regions. The particle types may be red, green and blue particles where each colour responds to voltages in a different range. A plurality of capsules each contain a fluid suspending some of each particle type, the position of the capsules being fixed by a binder film. A gamma voltage generating section 240 applies gamma voltages 242, 244, 246 in three different ranges, to cause one of the types of particles to perform electrophoresis and hence to change the colour of the pixel regions to which the voltage is applied.

Description

I

ELECTRONIC INK PANEL, ELECTRONIC INK DISPLAY DEVICE HAVING THE SAME, AND METHOD FOR DRIVING THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2006- 0046528, filed on May 24, 2006, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUJND

1. Field of the Invention

[0001] The present invention relates to a flat panel display device, and more particularly to an electronic ink panel capable of displaying colours without a colour filter. Further, the present invention relates to an electronic ink display device including an electronic ink panel capable of displaying colours and a method for driving the same.

2. Discussion of Related Art [0002] A CRT (Cathode Ray Tube) which is one of general display devices is mainly used in a monitor of a measurement instrument and an information terminal device including a TV. The CRT makes the slimness and lightness of an electronic product difficult due to its weight and size.

[0003] As the information society has been developed, the requirements for display devices have been also increased. Therefore, various flat panel display device such as an LCD (Liquid Crystal Display) device, a PDP (Plasma Display Panel), and an ELD (Electro Luminescent Display) have been researched and some of them are used as display devices in various equipment.

[0004] Recently, an electronic ink display device called "a DPD (Digital Paper Display) device" has been suggested. The electronic ink display device can be manufactured by a low cost and can be driven by little energy, as compared with a conventional flat panel display device. Further, the electronic ink display device does not require a separate backlight unit and has a wide visual angle. In addition, the electronic ink display device can be repetitively bent without changing the resolution and the contrast. The electronic ink display device is applied to a portable computer, an electronic newspaper, a smart card, etc. Further, the electronic ink display device comes into the spotlight as a next-generation display device which can replace traditional print media such as books, newspapers, and magazines.

[0005] The electronic ink used in the electronic ink display device includes particles floatal5lj included in a capsulated fluid. The particles have a negative or positive charge so that electrophoresis can be performed to the particles. Accordingly, the electronic ink display device displays an image by applying electric fields to the electronic ink and regulating the electrophoresis of the particles in the electronic ink.

(00061 Actually, the electronic ink display device uses an electronic ink panel having a cross-section shown in FIG. 1. The electronic ink panel shown in FIG. 1 includes first and second substrates 2 and 4 facing each other, with a middle electronic ink layer 10 being interposed between them.

[0007] Gate electrodes 3 and gate wires (not shown) are formed on the second substrate 4. The gate wires are electrically connected to the gate electrodes 3. A gate insulation layers is formed on the second substrate 4 having the gate electrodes 3 and the gate wires. Channel layer patterns 7 are formed at portions corresponding to the gate electrodes 3 on the gate insulation layer 5. The channel layer patterns 7 are formed by forming a semiconductor material layer on the gate insulation layer 5 and patterning the semiconductor material layer. Source and drain electrodes 9A and 913 separated from each other are formed on the surface of each channel layer pattern 7.

Data wires (not shown) are formed together with the source and drain electrodes 9A and 9B. The data wire is electrically connected to the source electrode 9A. A protection layer 11 having contact holes is formed on the entire surface of the second substrate 4 in which the source and drain electrodes 9A and 9B are formed. Each of the contact holes exposes a portion of the surface of the corresponding drain electrode 9B. Second electrode patterns 8 electrically connected to the drain electrodes 9B are formed on the protection layer 11. Each of the second electrode patterns 8 is located in a sub-pixel region divided by the gate wires and the data wires.

10008] A black matrix is formed on the first substrate 2. The surface of the first substrate 2 is divided into a plurality of sub-pixel regions by the black matrix 19. A colour filter 18 is formed on the surface of the first substrate 2 which is exposed through the black matrix 19. The colour filter 18 includes sub-colour filters 1 8A, 1 8B, and 1 8C of red, green, and blue. A first electrode 6 is formed on the surfaces of the sub-colour filters 18 and the black matrix 19.

[0009] The first and second substrate 2 and 4 are disposed on both surfaces of the electronic ink layer 10 so that the first electrode 6 and the second electrode patterns 8 face each other. In other words, the electronic ink layer 10 is located between the first electrode 6 and the second electrode patterns 8. The electronic ink layer 10 includes a binder film 12 in which a micro-capsulated ink capsule 14 is dispersed and contained. The binder film 12 is formed of a polymer. The ink capsule has a diameter of approximately a few hundred micrometers. The ink capsule 14 includes a fluid 16 of one of an organic material and an inorganic material which is filled in the interior thereof. At least one kind of electrified particles 20 are injected into the fluid in the ink capsule 14. Electrophoresjs is performed with respect to the particles in response to an electric field applied between the first electrode 6 and the second electrode pattern 8 so that a colour image can be displayed on the first substrate 2 in which the colour filter 18 is formed.

[0010] Actually, the particles 20 include white first particles 22 of a positive charge and black second particles 24 of a negative charge. Electrophoresis is performed with respect to the first and second particles 22 and 24 according to the electric fields between the first electrode 6 and the second electrode patterns 8 so that an image corresponding to the gradation of white and black colours can be displayed on the electronic ink layer 10. As the black and white image on the electronic ink layer is projected to the first substrate 2 having the colour filter 18, a colour image appears on the electronic ink panel (i.e. the first substrate 2).

[0011] FIGs. 2A to 2C shows the electrophoresis state of the first and second particles 22 and 24 of FIG. 1 according to electric fields. As shown in FIG. 2A, if a voltage -V of the negative polarity is supplied to the first electrode 6 while a voltage +V of the positive polarity is supplied to the second electrode pattern 8, the white first particles 22 of a positive charge are concentrated to the first electrode 6 while the black second particles 24 of a negative charge are concentrated to the second electrode 8. In this case, the difference between the voltage-V of the negative polarity and the voltage +V of the positive polarity is set large enough to perform electrophoresis with respect to the first and second particles 22 and 24. By the white colour of the first particles 22 concentrated to the first electrode 6, a large amount of light from outside is reflected toward the colour filter 18. Therefore, sub-pixels of red, green, and blue of the highest gradation are displayed on the first substrate 2 according to the sub-colour filters 1 8A, 1 8B, and 1 8C.

[0012] On the contrary, as shown in FIG. 2B, if a voltage +V of the positive polarity is supplied to the first electrode 6 and a voltage -V of the negative polarity is supplied to the second electrode pattern 8, the white first particles 22 of a positive charge are concentrated to the second electrode 8 and the black second particles 24 of a negative charge are concentrated to the first electrode 6. The black colour of the second particles 24 concentrated to the first electrode 6 absorbs almost all the light from outside. Therefore, sub-pixels of red, green, and blue of the lowest gradation are displayed on the first substrate 2 according to the sub-colour filters 1 8A, 1 8B, and 18C.

[0013] Differently from FIGs. 2A and 2B, FIG. 2C shows the case in which voltages +V of the positive polarity or voltages -v of the negative polarity or voltages of very small voltage differences are supplied to all of the first electrode 6 and the second electrode pattern 8. In this case, the first and second particles 22 and 24 are concentrated to a central portion between the first electrode 6 and the second electrode pattern S by the attractive force. About a half of the light from outside is reflected toward the colour filter 18 by the white colour of the first particles 22 and the black colour of the second particles 24. Therefore, sub-pixels of red, green, and blue which have a middle gradation are displayed on the first substrate 2 according to the sub-colour filters I 8A, 1 8B, and 1 8C.

[0014] As mentioned above, the conventional electronic ink panel includes the colour filter 18 to display a colour image. The colour filter 18 reflects some of the light to be transmitted, thereby acting as a factor deteriorating the optical efficiency of the electronic ink panel. Further, the colour filter increases the thickness of the electronic ink panel and complicates the manufacturing process of the electronic ink panel.

SUMMARY OF TIlE INVENTION

[0015] Accordingly, the present invention is directed to an electronic ink panel that substantially obviates one or more of the problems due to limitations and disadvantages of the related art, and an electronic ink display device having the same and a method for driving the same.

[0016] Therefore, the present invention seeks to provide an electronic ink panel capable of displaying a colour image without a colour filter, an electronic ink display device including the same, and a method for driving the same.

[0017] Seeking to achieve this, according to a first aspect of the invention there is provided an electronic ink panel comprising: an electronic ink layer comprising first to third particles responding to voltages in different level ranges; a first substrate in which a first electrode facing one surface of the electronic ink layer is formed; and a second substrate in which second electrodes of a size of a pixel region which faces the other surface of the electronic ink layer is formed.

[0018] According to another aspect of the present invention, there is provided an electronic ink display device comprising: an electronic ink panel comprising an electronic ink layer comprising particles of red, green, and blue colours which performs electrophoresis by voltages in different level ranges and substrates in which wire patterns dividing and driving the electronic ink layer to the sizes of sub-pixel regions are formed; a gamma voltage generating section generating first to third gamma voltage sets having at least two gradation voltages in level ranges corresponding to the red, green, and blue particles; and a drive section driving wire patterns on the electronic ink panel so that one of the red, green, and blue particles performs electrophoresis in the sub-pixel region using the first to third gamma voltage sets in response to a data steam comprising sub-pixel data of red, green, and blue.

[0019] According to another aspect of the present invention, there is provided a method for driving an electronic ink display device comprising an electronic ink panel comprising an electronic ink layer comprising particles of red, green, and blue colours which performs electrophoresis by voltages in different level ranges and substrates in which wire patterns dividing and driving the electronic ink layer to the sizes of sub-pixel regions are formed. The method comprises the steps of: generating first to third gamma voltage sets having at least two gradation voltages in level ranges corresponding to the red, green, and blue particles; converting sub-pixel data of red, green, and blue in the form of a data stream to sub-pixel data voltages of red, green, and blue in the form of analog by using the first to third gamma voltage sets; and allowing one of the red, green, and blue particles to perform electrophoresis in pixel regions by supplying sub-pixel data of red, green, blue to the wire pattern of the electronic ink panel.

[0020] Additional advantages and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

[0021] It is to be understood that both the foregoing general description and the following detailed description of embodiments of the present invention are exemplary and explanatory, and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention.

[0023] FIG. 1 is a cross-sectional view showing an electronic ink panel of a conventional electronic ink display device; [0024] FIGs. 2A to 2C are circuit diagrams for explaining the electrical electrophoresis state of the electronic ink shown in FIG. 1; [0025] FIG. 3 is a block diagram for explaining an electronic ink display device according to a preferred embodiment of the present invention; [0026] FIG. 4 is a cross-sectional view for explaining the electronic ink panel shown in FIG. 3; and [0027] FIGs. 5A to SC are circuit diagrams for explaining the first to third gamma voltage generators shown in FIG. 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] Hereinafter, preferred embodiments according to the present invention will be described with reference to the accompanying drawings.

[0029] FIG. 3 is a block diagram for explaining an electronic ink display device according to a preferred embodiment of the present invention. Referring to FIG. 3, the electronic ink display device according to the present invention includes an electronic ink panel 232 displaying a colour image. A plurality of gate lines GL 1 to GLn and a plurality of data lines DLI to DLm cross each other on the electronic ink panel 232.

The display region of the electronic ink panel 232 is divided into a plurality of sub- pixel regions by the gate lines GLI to GLn and the data lines DL1 to DLm. A sub-pixel is formed in each of the sub-pixel regions. The sub-pixel includes a thin film transistor TFT connected between the corresponding gate line GL, the corresponding data line DL, and the corresponding electronic ink cell (EIC). The thin film transistor TFT switches a sub-pixel voltage which is to be transferred from the corresponding data line DL to the corresponding electronic ink cell EIC in response to a gate signal on the corresponding gate line GL. The electronic ink panel 232 having the plurality of sub-pixels has a cross-section as shown in FIG. 4.

[0030] The electronic ink panel 232 shown in FIG. 4 includes first and second substrates 202 and 204 facing each other about the electronic ink layer 210. Substrates formed of a transparent insulation material (e.g. one of glass and plastic) are used as the first and second substrates 202 and 204. It is preferable that plastic substrates which can be repetitively bent or deformed are used as the first and second substrates 202 and 204 instead of glass substrates.

[0031J Gate electrodes 203 and gate lines GL (not shown) are formed on the second substrate 204. The gate lines GL are electrically connected to the gate electrodes 203. A gate insulation layer 205 is formed on the second substrate 204 having the gate electrodes 203 and the gate lines GL. Channel layer patterns 207 are formed at portions corresponding to the gate electrodes 203 on the gate insulation layer 205. The channel layer patterns 207 are formed by forming a semiconductor material layer on the gate insulation layer 5 and patterning the semiconductor material layer. Source and drain electrodes 209A and 209B separated from each other are formed on a surface of each of the channel layer patterns 207. Data lines DL (not shown) are formed together with the source and drain electrodes 209A and 209B. The data lines DL are electrically connected to the source electrode 209A. The gate electrode 203, the channel layer pattern(207), and the source and drain electrodes 209A and 209B constitutes the thin film transistor TFT of FIG. 3. Then, a protection layer having contact holes CH are formed on the entire surface of the second substrate 204 in which the source and drain electrodes 209A and 209B. Each of the contact holes CU exposes a portion of a surface of the drain electrode 209B. Second electrode patterns 208 electrically connected to the drain electrodes 209B are formed on the protection layer 211. Each of the second electrode patterns 208 is located in a sub-pixel region divided by the gate line and the data line DL to be used as a sub-pixel electrode. Further, each of the second electrode patterns 208 forms a sub-pixel together with the corresponding thin film transistor TFT. More particularly, the first pixel electrode 208A and the thin film transistor TFT connected to the first pixel electrode 208A form a first sub-pixel and the second pixel electrode 208B and the thin film transistor TFT connected to the second pixel electrode 208B form a second sub-pixel.

Further, the third pixel electrode 208C and the thin film transistor TFT connected to the third pixel electrode 208C form a third sub-pixel. In addition, each of the second electrode patterns 208 (i.e. the first to third pixel electrodes 208A to 208C) constitutes an electronic ink cell (EIC) together with the electronic ink layer portion at an upper portion thereof.

(0032] On the other hand, a first electrode 206 is formed on the entire surface of the first substrate 202. The first electrode 206 is formed of a conductive material (e.g. ITO) like the second electrode patterns (i.e. the first to third pixel electrodes 208A to 208C).

[0033] The first and second substrates 202 and 204 are disposed both sides of the electronic ink layer 210, respectively, with the first electrode 206 and the second electrode patterns 208 facing each other. The electronic ink layer 210 includes a binder film 212 in which ink capsules 214 are dispersed and contained. The binder film 212 fixes the ink capsules 214 so that the ink capsules 214 cannot be moved and functions as a cross-linker for electrical and physical division. For this, the binder film 212 is formed of one of dielectric materials such as soluble, water-dispersed, liposoluble, thermosetting, and thermoplastic polymers and photo-polymerizable polymers.

[0034] A fluid 216 is filled in the ink capsule 214 and includes particles 220.

The ink capsule 214 is formed of an organic material capable of stably protecting the fluid 216. The fluid 216 is formed of a transparent and translucent material which maintains the viscosity enabling electrophoresis of the particles 220 and has a high resistance. For example, the fluid 216 can be formed of an inorganic material. Further, a mixture fluid in which at least two materials are mixed can be used as the fluid 216.

[0035] In another method, the fluid 216 can be dyed in red, green, and blue according to the sub-pixels. In this case, differently form the ink capsule 214, the fluid 216 can be divided into the size of the sub-pixel region by the partition walls. The particles shown in FIG. 1 can be used as the particles 220 contained in the fluid 216.

[0036] The particles 220 injected into the ink capsule 214 include first to third particles 222, 224, and 226. In other words, the first to third particles 222, 224, and 226 are injected into the ink capsule 214 together with the fluid 216. The red first particles 222 of a positive charge, the green second particles 224 of a positive charge, and the blue third particles 226 can be injected into the ink capsule 220. In another form, the first particles can red and of a negative charge, the second particles can be green and of a negative charge, and the third particles 226 can be blue and of a negative charge.

(0037] All of the first to third particles 222 to 226 reacts only with voltages in different level ranges regardless of its positive or negative charges. In other words, The first to third particles 222 to 226 performs electrophoresis toward the first electrode 206 used as the common electrode or the second electrode pattern 208 used as the pixel electrode in response to the voltages in the different level ranges.

[0038] For example, the first particles 222 performs electrophoresis toward the first electrode 206 when a voltage in a low level range is applied between the first electrode 206 and the second electrode pattern 208 to display the red colour of the gradation corresponding to the voltage. The second particles 224 performs electrophoresis toward the first electrode 206 when a voltage in a middle level range is applied between the first electrode 206 and the second electrode pattern 208 to display the green colour of the gradation corresponding to the voltage. The third particles 226 performs electrophoresis toward the first electrode 206 when a voltage in a high level range is applied between the first electrode 206 and the second electrode pattern 208 to display the blue colour of the gradation corresponding to the voltage.

[0039] In addition, a sub-pixel data voltage in a low level range can be supplied between the first electrode 206 and one of the second electrode patterns 208, e.g. a first sub-pixel electrode 208A, a sub-pixel data voltage in a high level range can be supplied between the first electrode 206 and another of the second electrode patterns 208, e.g. a second sub-pixel electrode 208B, and a sub-pixel data voltage in a high level range can be supplied between the first electrode 206 and the other of the second electrode patterns 208, e.g. a third sub-pixel electrode 208C. In this case, the electrophoresis of the red first particles 222 is performed in the ink capsules 214 at an upper portion of the first pixel electrode 208A, the electrophoresis of the green second particles 224 is performed in the ink capsules 224 at an upper portion of the second pixel electrode 208B, and the electrophoresis of the blue third particles 226 is performed in the ink capsules 214 at an upper portion of the third pixel electrode 208C. Therefore, the region of the first pixel electrode 208A can be driven as a red sub-pixel displaying the red colour of a plurality of gradations, the region of the second pixel electrode 208B as a green sub-pixel displaying the green colour of a plurality of gradations, and the region of the third pixel electrode 208C as a blue sub-pixel displaying the blue colour of a plurality of gradations. One colour pixel displaying various colours is constituted by the red, green, and blue sub-pixels.

[0040] In this way, the electronic ink panel 232 allows one of the red, green, and blue particles responding to voltages of different levels to selectively perform the electrophoresis according to the sub-pixel to use the one of the red, green, and blue particles to be used as a sub-pixel. Accordingly, the electronic ink panel 232 can display the colour image without a colour filter. Further, the electronic ink panel 232 can be slimmed by removing the colour filter, thereby simplifying the manufacturing process.

[0041] Referring to FIG. 3 again, the electronic ink display device according to the preferred embodiment of the present invention includes a gate driver 234 for driving the plurality of gate lines GL I to GLn on the electronic ink panel 232; a data driver 236 for driving the plurality of data lines DLI to DLm on the electronic ink panel 232; a timing controller 238 for controlling the gate driver 234 and the data driver 236; and a gamma voltage generating section 240 for supplying a gamma voltage to the data driver 236.

[0042] The gate driver 234 supplies a plurality of scan signals to the plurality of gate lines GL 1 to GLn in response to the gate control signal supplied from the timing controller 238. The plurality of scan signals have enable pulses sequentially shifted by a predetermined period (e.g. a period corresponding to the period of horizontal synchronous signals). Accordingly, the plurality of gate lines GL 1 to (3Ln are sequentially enabled by the plurality of scan signals by periods.

[0043] The data driver 236 supplies pixel data voltages to the plurality of data lines DL1 to DLm in response to data control signals supplied from the timing controller 238. For this, the data driver 236 inputs red, green, and blue sub-pixel data by one line from the timing controller 238. The data driver 236 converts the sub-pixel data of red, green, and blue of one line to analog sub-pixel data voltages using the gamma voltage sets from the gamma voltage generating section 240. The sub-pixel data voltages of red, green, and blue of one line, which is converted by the data driver 236 are supplied to the plurality of data lines DL! to DLm on the electronic ink panel 232.

[0044) The timing controller 238 generates a gate control signal to be supplied to the gate driver 234 and a data control signal to be supplied to the data driver 236, using a vertical/horizontal synchronous signal VsyncfHsync supplied from a system (not shown), a data enable signal DE, and a clock signal. Further, the timing controller 238 rearranges the data stream of the red, green, and blue sub-pixel data supplied form an external system by one line. The timing controller 238 supplies the rearranged red, green, and blue sub-pixel data to the data driver 236 by one line.

[0045] The gamma voltage generating section 240 supplies the first to third gamma voltage sets pertaining to different level ranges to the data driver 236. For this, the gamma voltage generating section 240 includes first to third gamma voltage generators 242 to 246. The first gamma voltage generator 242 generates a first gamma voltage set of a first level range (for example, a low level range) for performing electrophoresis to the first particle 222 contained in the ink capsule 214 of the liquid crystal panel 232. The second gamma voltage generator 244 generates a second gamma voltage set of a second level range (for example, a middle level range) for performing electrophoresis to the second particle 224 contained in the ink capsule 214 of the liquid crystal panel 232. The third gamma voltage generator 246 generates a third gamma voltage set of a third level range (for example, a high level range) for performing electrophoresis to the third particle 226 contained in the ink capsule 214 of the liquid crystal panel 232.

[0046] The data driver 236 inputhng the first to third gamma voltage sets converts the red sub-pixel data of the sub-pixel data of one line to sub-pixel data voltages pertaining to a low level range by the first gamma voltage set. The sub-pixel data voltages in the low level range are supplied to the first pixel electrode 208A so that only the red first particles 222 of the particles 222 to 226 in the ink capsule 214 at an upper portion of the first pixel electrode 208A can be concentrated to thefirst electrode 206 to display the red colour of the gradation corresponding to the logic values of the red sub-pixel data. The data driver 236 converts the green sub-pixel data of the sub-pixel data of one line to sub-pixel data voltages pertaining to a middle level range by the second gamma voltage set. The sub-pixel data voltages in the middle level range are supplied to the second pixel electrode 208B so that only the green second particles 224 of the particles 222 to 226 in the ink capsule 214 at an upper portion of the second pixel electrode 208B can be concentrated to the first electrode 206 to display the green colour of the gradation corresponding to the logic values of the green sub-pixel data. The data driver 236 converts the blue sub-pixel data of the sub-pixel data of one line to sub-pixel data voltages pertaining to a high level range by the third gamma voltage set. The sub-pixel data voltages in the high level range are supplied to the third pixel electrode 208C so that only the blue third particles 226 of the particles 222 to 226 in the ink capsule 214 at an upper portion of the third pixel electrode 208C can be concentrated to the first electrode 206 to display the blue colour of the gradation corresponding to the logic values of the blue sub-pixel data.

Accordingly, a colour image corresponding to the sub-pixel data stream of one frame is displayed on the electronic ink panel.

[0047] As mentioned above, in the electronic ink display device according to embodiments of the present invention, the red, green, and blue sub-pixel data voltages in different level ranges are supplied to the data lines of the electronic ink panel containing the red, green, and blue particles responding voltages in different level ranges. One of the red, green, and blue colours of the gradation corresponding to the logic value of the sub-pixel data is displayed by selectively performing electrophoresis with respect to one of the red, green, and blue particles on the electronic ink panel according to the sub-pixel. Consequently, the electronic ink display device according to the present invention can display a colour image corresponding to the sub-pixel data stream of one frame on the electronic ink panel without a colour filter. In addition, the electronic ink display device according to the present invention can be slimmed further since the thickness of the electronic ink panel becomes thinner.

[0048] FIGs. 5A to 5C are circuit diagrams for explaining the first to third gamma voltage generators 242, 244, and 246 shown in FIG. 3.

[0049] The first gamma voltage generator 242 shown in FIG. 5A includes a first resistance string including a plurality of resistances Ru to Rin. The plurality of resistances Ri 1 to RI n included in the first resistance string are connected in series between input lines of a first power source voltage Vi and the base voltage OND. The divided voltages Vgl 1, Vg12, ... generated at connection points between the plurality of resistances RI I to Rin are supplied to the data driver 236 as a first gamma voltage set. The voltages Vgll, Vg12, ... divided by the plurality of resistances Ru to Rin have different voltage levels in a low level range between the first power source voltage Vi and the base voltage.

[0050] The second gamma voltage generator 244 shown in FIG. 5B includes a second resistance string including a plurality of resistances R2 I to R2n. The plurality of resistances R21 to R2n included in the second resistance string are connected in series between input lines of a first power source voltage Vi and a second power source voltage V2. The divided voltages Vg2 1, Vg22, ... generated at connection points between the plurality of resistances R2 1 to R2n are supplied to the data driver 236 as a second gamma voltage set. The voltages Vg21, Vg22, ... divided by the plurality of resistances R21 to R2n have different voltage levels in a middle level range between the first power source voltage VI and the second power source voltage V2. The first power source voltage Vi supplied to the second gamma voltage generator 244 of FIG. 5B has the same voltage level of that of the first power source voltage Vi supplied to the first gamma voltage generator 242 of FIG. 5A.

[0051] As shown in FIG. 5C, the third gamma voltage generator 246 includes a third resistance string including a plurality of resistances R31 to R3n. The plurality of resistances R3 I to R3n included in the third resistance siring are connected in series between input lines of a third power source voltage V3 and a second power source voltage V2. The divided voltages Vg3 I, Vg32, ... generated at connection points between the plurality of resistances R3 1 to R3n are supplied to the data driver 236 as a third gamma voltage set. The voltages Vg3 1, Vg32, ... divided by the plurality of resistances R3 1 to R3n have different voltage levels in a high level range between the third power source voltage V3 and the second power source voltage V2. The second power source voltage V2 supplied to the third gamma voltage generator 246 of FIG. 5C has the same voltage level of that of the second power source voltage V2 supplied to the second gamma voltage generator 242 of FIG. 5B.

[0052] In another method, the first power source voltage Vi supplied to the first gamma voltage generator 242 of FIG. 5A can be higher than the first power source voltage Vi supplied to the second gamma voltage generator 244 of FIG. 5B and the second power source voltage V2 supplied to the second gamma voltage generator of FIG. 5B can also be higher than the second power source voltage V2 supplied to the third gamma voltage generator 246 of FIG. 5C. In this case, the lower second gamma voltages of the second gamma voltage set are superposed with the upper second gamma voltages of the first ganmia voltage set and the upper second gamma voltages of the second gamma voltage set are superposed with the lower third gamma voltages of the third gamma voltage set. In this way, since the second gamma voltage set in the middle level range is partially superposed with the first gamma voltage set in the low level range and the third gamma voltage set in the high level range, electrophoresis can be performed with respect to two kinds of particles of the first to third particles 222 to 226. Accordingly, the optical usability of the electronic ink panel 232 and the cleanness of the image can be improved.

[0053] As mentioned above, the electronic ink panel allows one of the red, green, and blue particles responding to voltages of different levels to selectively perform the electrophoresjs according to the sub-pixel to use the one of the red, green, and blue particles to be used as a sub-pixel. Accordingly, the electronic ink panel can display the colour image without a colour filter. Further, the electronic ink panel can be slimmed by removing the colour filter, thereby simplifying the manufacturing process.

[0054] Further, in the electronic ink display device and the method for driving the electronic ink display device according to embodiments of the present invention, the red, green, and blue sub-pixel data voltages in different level ranges are supplied to the data lines of the electronic ink panel including the red, green, and blue particles responding to the voltages in different level ranges. Further, one of the red, green, and blue colours of the gradation corresponding to the logic value of sub-pixel data is displayed by selectively performing electrophoresis with respect to only one kind of particles of the red, green, and blue particles on the electronic ink panel according to the sub-pixel. Consequently, the electronic ink display device and the method for driving the electronic ink display device according to the present invention can display the colour image corresponding to the sub-pixel data stream of one frame on the electronic ink panel without a colour filter. In addition, since the electronic ink display device according to the present invention has the electronic ink panel the thickness of which becomes thinner, it can be slimmed further.

[0055] Although preferred embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes might be made in those embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

CLAIMS

1. An electronic ink panel comprising: an electronic ink layer comprising first to third particles responding to voltages in different level ranges; a first substrate in which a first electrode facing one surface of the electronic ink layer is formed; and a second substrate in which second electrodes of a size of a pixel region which faces the other surface of the electronic ink layer is formed.

2. An electronic ink panel according to claim 1, wherein the first to third particles have red, green, and blue colours.

3. An electronic ink panel according to claim 2, wherein the electronic ink layer comprises capsules into which the first to third particles have been injected.

4. An electronic ink panel according to claim 3, wherein the capsule comprises a fluid enabling free electrophoresis of the first to third particles and maintaining the electrophoresis positions of the first to third particles.

5. An electronic ink panel according to claim 4, wherein the fluid is one of an organic material and an inorganic material.

6. An electronic ink panel according to claim 4 or 5, wherein the electronic ink layer comprises a binder film fixing the position of the capsule.

7. An electronic ink panel according to claim 2, wherein the electronic ink layer comprises a fluid enabling free electrophoresis of the first to third particles and maintaining the electrophoresjs positions of the first to third particles.

8. An electronic ink panel according to claim 7, wherein the electronic ink layer comprises a binder film which the fluid divides to the size of the second electronic pattern.

9. An electronic ink panel according to any preceding claim, wherein the second substrate further comprises: gate lines selecting the second electrode patterns by rows; data lines supplying data voltages to the second electrode patterns by columns; and a switch device located at cross portions between the gate lines and the data lines, the switch device switching the data voltage to be supplied to the corresponding second electrode pattern from the corresponding data line in response to a signal on the corresponding gate line.

10. An electronic ink display device comprising: an electronic ink panel comprising an electronic ink layer comprising particles of red, green, and blue colours which performs electrophoresis by voltages in different level ranges and substrates in which wire patterns dividing and driving the electronic ink layer to the sizes of sub-pixel regions are formed; a gamma voltage generating section generating first to third gamma voltage sets having at least two gradation voltages in level ranges corresponding to electroplioresis levels of the red, green, and blue particles; and a drive section driving wire patterns on the electronic ink panel so that one of the red, green, and blue particles performs electrophoresjs in the sub-pixel region using the first to third gamma voltage sets in response to a data steam comprising sub-pixel data of red, green, and blue.

11. An electronic ink display device according to claim 10, wherein the red particle performs electrophoresis with a voltage in a low level range, the green particle performs electrophoresis with a voltage in a middle level range, and the blue particle performs electrophoresis with a voltage in a high level range.

12. An electronic ink display device according to claim 11, wherein the first gamma voltage set comprises at least two voltages in a low level range, the second gamma voltage set comprises at least two voltages in a middle level range, and the third gamma voltage set comprises at least two voltages in a high level range.

13. An electronic ink display device according to claim 11, wherein the gamma voltage set of the first to third gamma voltage sets which occupies the middle level range comprises a gamma voltage of a gradation superposed with the other sets.

14. A method for driving an electronic ink display device comprising an electronic ink panel comprising an electronic ink layer comprising particles of red, green, and blue colours which performs electrophoresis by voltages in different level ranges and substrates in which wire patterns dividing and driving the electronic ink layer to the sizes of sub-pixel regions are formed, the method comprising the steps of: generating first to third gamma voltage sets having at least two gradation voltages in level ranges corresponding to the red, green, and blue particles; converting sub-pixel data of red, green, and blue in the form of a data stream to sub-pixel data voltages of red, green, and blue in the form of analog by using the first to third gamma voltage sets; and allowing one of the red, green, and blue particles to perform electrophoresis in pixel regions by supplying sub-pixel data of red, green, blue to the wire pattern of the electronic ink panel.

15. A method according to claim 14, wherein the red particle performs electrophoresis with a voltage in a low level range, the green particle performs electrophoresis with a voltage in a middle level range, and the blue particle performs electrophoresis with a voltage in a high level range.

16. A method according to claim 14 or 15, wherein the first gamma voltage set comprises at least two voltages in a low level range, the second gamma voltage set comprises at least two voltages in a middle level range, and the third gamma voltage set comprises at least two voltages in a high level range.

17. A method according to claim 14 or 15, wherein the gamma voltage set of the first to third gamma voltage sets which occupies the middle level range comprises a gamma voltage of a gradation superposed with the other sets.

18. An electronic ink panel, substantially as hereinbefore described with reference to Figs. 3 to 5C of the accompanying drawings.

19. A method for driving an electronic ink display device, substantially as hereinbefore described with reference to Figs. 3 to 5C of the accompanying drawings.

20. A display device, comprising an electronic ink panel according to any of claims 1 to 13 or 19.